1. Technical Field
The present invention relates to an image display device and a method of displaying the image.
2. Related Art
In association with development of IT technology in the recent years, a need of image display devices is increased in various fields. Among such image display devices, a liquid crystal projector that projects an image emitted from an optical system using a liquid crystal light valve onto a screen via a projection lens in an enlarged scale is widely used as a mode of a liquid crystal display device that can change optical characteristics by electrically controlling an array of liquid crystal molecules.
The liquid crystal projector employs the liquid crystal light valve as light modulating means. However, since the range of brightness that can be displayed (dynamic range) is narrow due to light leakage or stray light generated at various optical components that constitute the optical system, it is difficult to improve the quality of the image. Therefore, as a method of enlarging the dynamic range, a method of changing the light amount incoming into the liquid crystal light valve according to an image signal (light modulation process) while expanding the image signal (expansion process) (adaptive image processing) has been proposed in the related art.
The liquid crystal projector as described above receives supply of image signals, that is, an image from an image supply device such as a DVD (Digital Versatile Disk) player, a video player, or a PC (Personal Computer), and projects the image onto a screenin an enlarged scale. The image supply device as described above applies γ correction on the image signal corresponding to γ characteristics of the liquid crystal projector, and supplies the image signal after having applied with the γ correction to the liquid crystal projector. There is no problem when the predetermined image supply device is connected to the liquid crystal projector. However, there is a problem such that when another different image supply device is connected thereto, since the γ correction process for the image signal is also different, mismatch with the γ characteristics of the liquid crystal projector may occur, and consequently, a desired image display cannot be achieved. In particular, the liquid crystal projector having an adaptive image processing function as described above has a problem such that if the supplied image signal varies according to the image supply device to be connected, the adaptive image processing function does not work effectively.
In order to prevent the mismatch between the γ characteristics of the image display device and the γ correction of the image supply device, for example, JP-A-2004-96556 discloses a technique for achieving a suitable image display with an image display device that displays the image signal supplied from the image supply device by supplying an image signal of a specific pattern from the image supply device, detecting a γ value of the image signal of the specific pattern, calculating a correction value from a detected γ value and a γ value of the image display device, and applying the γ correction on the image signal on the basis of the correction value without depending on the image supply device.
However, in recent years, an image display device with a high-performance such as applying γ correction differently for each color signal (RGB) or applying γ correction differently according to image scenes is required for further improving the quality of image display. In order to apply several types of γ corrections as described above, it is necessary to apply very complicated γ correction process for preventing the mismatch between the γ characteristics of the image display device and the γ correction of the image supply device, and hence there arises a problem such that a response of the image processing is delayed.